Add hosts settings and some validation logic

scripts/local_with_uvicorn/.env.example

@@ -16,6 +16,8 @@
 APP_NAME="My Project"
 APP_DESCRIPTION="My Project Description"
 APP_VERSION="0.1"
+APP_BACKEND_HOST="http://localhost:8000"
+APP_FRONTEND_HOST="http://localhost:3000"
 CONTACT_NAME="Me"
 CONTACT_EMAIL="[email protected]"
 LICENSE_NAME="MIT"

src/app/core/config.py

@@ -1,18 +1,31 @@
 import os
+import warnings
 from enum import Enum
+from typing import Self
 
-from pydantic import SecretStr, computed_field
+from pydantic import SecretStr, computed_field, field_validator, model_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
 class AppSettings(BaseSettings):
     APP_NAME: str = "FastAPI app"
     APP_DESCRIPTION: str | None = None
     APP_VERSION: str | None = None
+    APP_BACKEND_HOST: str = "http://localhost:8000"
+    APP_FRONTEND_HOST: str | None = None
     LICENSE_NAME: str | None = None
     CONTACT_NAME: str | None = None
     CONTACT_EMAIL: str | None = None
 
+    @field_validator("APP_BACKEND_HOST", "APP_FRONTEND_HOST", mode="after")
+    @classmethod
+    def validate_hosts(cls, host: str) -> str:
+        if host is not None and not (host.startswith("http://") or host.startswith("https://")):
+            raise ValueError(
+                f"HOSTS must define their protocol and start with http:// or https://. Received the host '{host}'."
+            )
+        return host
+
 
 class CryptSettings(BaseSettings):
     SECRET_KEY: SecretStr = SecretStr("secret-key")
@@ -172,5 +185,30 @@ class Settings(
         extra="ignore",
     )
 
+    @model_validator(mode="after")
+    def validate_environment_settings(self) -> Self:
+        "The validation should not modify any of the settings. It should provide"
+        "feedback to the user if any misconfiguration is detected."
+        if self.ENVIRONMENT == EnvironmentOption.LOCAL:
+            pass
+        elif self.ENVIRONMENT == EnvironmentOption.STAGING:
+            if "*" in self.CORS_ORIGINS:
+                warnings.warn(
+                    "For security, in a staging environment CORS_ORIGINS should not include '*'. "
+                    "It's recommended to specify explicit origins (e.g., ['https://staging.example.com'])."
+                )
+        elif self.ENVIRONMENT == EnvironmentOption.PRODUCTION:
+            if "*" in self.CORS_ORIGINS:
+                raise ValueError(
+                    "For security, in a production environment CORS_ORIGINS cannot include '*'. "
+                    "You must specify explicit allowed origins (e.g., ['https://example.com', 'https://www.example.com'])."
+                )
+            if self.APP_FRONTEND_HOST and not self.APP_FRONTEND_HOST.startswith("https://"):
+                raise ValueError(
+                    "In production, APP_FRONTEND_HOST must start with the https:// protocol. "
+                    f"Received the host '{self.APP_FRONTEND_HOST}'."
+                )
+        return self
+
 
 settings = Settings()